| Abstract |
The main advantage of electric robotic drives is their easy and fast electronic-power control: Beginning with the supply of d.c. motors by controlled rectifier-bridges the d.c. commutator-machine changed from the cylindric-rotor to the disc-rotor-type, especially for robotic-arm-drives where extremely short motors are required. With the increasing power density of permanent magnet materials the brushless "synchronous"-respectively e.c. motors were developed. For main axes there is a trend to direct drives with switched reluctance motors, in future perhaps liquid cooled. A general trend goes to slotless permanent-magnet-excited drives with air gap windings, because they may give as well very high positioning accuracy at low speed as very low losses at high-speed running. Another trend goes to the intelligent drive system, demonstrated with a thermal-protection-system. |
